1. Field of the Invention
This invention relates to a process for the selective production of isopropylbenzene by catalytic propylation of benzene in the presence of a particular crystalline zeolite catalyst.
2. Description of the Prior Art
Alkylation of aromatic hydrocarbons utilizing crystalline zeolite catalysts has heretofore been described. U.S. Pat. No. 2,904,607 to Mattox refers to alkylation of aromatic hydrocarbons with an olefin in the presence of a crystalline metallic aluminosilicate having uniform pore openings of about 6 to 15 Angstrom unit. U.S. Pat. No. 3,251,897 to Wise describes alkylation of aromatic hydrocarbons in the presence of X- or Y-type crystalline zeolites, specifically such type zeolites wherein the cation is rare earth and/or hydrogen. U.S. Pat. No. 3,751,504 to Keown et al. and U.S. Pat. No. 3,751,506 to Burress describe vapor phase alkylation of aromatic hydrocarbons with olefins in the presence of a specified type of zeolite catalyst.
U.S. Pat. No. 3,755,483 to Burress discloses vapor phase alkylation of aromatic hydrocarbons in the presence of ZSM-12 zeolite catalyst. The reaction is carried out at temperatures between the critical temperature of the aromatic compound and 482.degree. C. (900.degree. F.). The critical temperature and pressure of benzene are 288.9.degree. C. (552.degree. F.) and 48.6 atm. (4.9.times.10.sup.6 N/m.sup.2).
Harper et al. have described the catalytic alkylation of benzene with propylene over a crystalline zeolite (Petrochemical Preprints, American Chemical Society, Vol. 22, No. 3, p. 1084, 1977). Extensive kinetic and catalyst aging studies were conducted with a rare earth-exchanged Y-type zeolite (REY) catalyst.
While the above-noted prior art is considered of interest in connection with the subject matter of the present invention, the propylation reaction described herein carried out at a temperature of between about 100.degree. C. and about the critical temperature in the presence of the particular type of catalyst disclosed to selectively yield isopropylbenzene has not, insofar as is known, been heretofore described.